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Vancelot's avatar
Vancelot
Copper Contributor
Feb 19, 2024

EAC Issue After Exchange 2019 CU14 Install

We upgraded our Exchange 2019 server from CU13 to CU14 successfully. This is a hybrid setup and we only use this server as a SMTP relay to Office 365. There are no mailboxes on-prem. Mail flow is wo...
Exchange Server
hybrid
office 365
Vancelot's avatar
Vancelot
Copper Contributor
Mar 07, 2024
I finally got Microsoft support involved. They went through all the basic troubleshooting steps that did not fix it. What they finally did to resolve it was to disable Extended Protection for Windows Authentication on the ECP and Powershell backend applications in IIS.
  • bobdowden's avatar
    bobdowden
    Copper Contributor
    Mar 08, 2024

    Vancelot 

     

    Hi, do you know how they did this?

    • Vancelot's avatar
      Vancelot
      Copper Contributor
      Mar 08, 2024
      In IIS --> Sites --> Exchange Back End --> ECP --> Authentication --> Windows Authentication --> Advanced Settings --> Set Extended Protection to "Off"
      Do the same for Powershell under Exchange Back End.
      Do an IISReset to restart IIS.
      • bobdowden's avatar
        bobdowden
        Copper Contributor
        Mar 11, 2024

        Vancelot 

        Thanks, I have mine sorted now, applied the changes which fixed the power hell issue, and probably will fix the ecp issue for anyone who had not messed with some other settings, but managed to undo those.

         

        Many thanks, much appreciated

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